1. Field of the Invention
The present invention relates to a proxy service providing apparatus using a plurality of devices connected to a network, a control method, and a network system.
2. Description of the Related Art
There are presently various digital home appliances, and partial networking to connect them has been implemented. For example, P2P (Peer To Peer) networking for a specific purpose is used to, for example, connect digital video recorders via IEEE1394 or connect a digital BS tuner to a D-VHS recorder via a PC. A home automation system using ECHONET executes centralized management of home air conditioning and illumination via a power line or wireless LAN.
The physical network type and connection procedure used for device networking change depending on the devices. To use an IP network, it is necessary to automatically set parameters in an environment without either a DHCP server or DNS server.
The UPnP Forum is pursuing standardization of a protocol to implement, in various physical networks, a function of automatically recognizing and setting devices connected to a network. The protocol is called UPnP (Universal Plug & Play). Use of UPnP allows each device to properly set network parameters by itself even in an environment without either a DHCP server or DNS server so that UPnP supporting devices can be aware of each other's existence, functions, and states.
FIG. 3 is a block diagram showing the basic arrangement of a UPnP network. A UPnP network is formed from three basic units: device, service, and control point. A device is a nested device serving as a service container. Each device has a device description that saves property information such as the device name and service set associated with itself. Another category is assigned to another service or nested device.
Referring to FIG. 3, an apparatus A 301 nests a device A 305 serving as the service container of a service A1 306 and a service A2 307. An apparatus B 302 nests a device B 308 serving as the service container of a service B 310. An apparatus C 303 nests a device C 311 serving as a Root device. The device C 311 serves as the service container of a service C1 313 and nests a built-in device 312 serving as the service container of a service C2 314 and a service C3 315. Each service such as the service A1, A2, B, C1, C2, or C3 is the minimum unit of control in the UPnP network. The service produces an action and models the state by using a state variable. A control point 304 serves as a controller to detect and control the remaining devices. The control point 304 may be incorporated in a device, like a control point B 309.
A network connected to UPnP supporting information processing apparatuses as shown in FIG. 8 will be examined as a prior art. Referring to FIG. 8, a control point (CP(a)) 801, UPnP camera 802, UPnP scanner 803, UPnP personal computer 804, and UPnP printer 805 connect to an IP network 806. The UPnP camera 802 includes a camera device 807 serving as the service container of a reproduction service 808 and a photographing service 809. The UPnP scanner 803 includes a scanner device 810 serving as the service container of a data scan service 811. The UPnP personal computer 804 includes a data device 812 serving as the service container of a data saving service 813 and a data transmission/reception service 814. The UPnP printer 805 includes a printer device 815 serving as the service container of a print service 816.
The UPnP camera 802 to UPnP printer 805 have a UPnP function. These connected devices multicast identification information (SSDP advertise message) to the IP network 806 at a predetermined interval when and after they connect to the IP network 806 and become usable from the CP(a) 801.
The CP(a) 801 searches for a device connected to the IP network 806 (by SSDP discovery message). A connected device matching the search condition replies to the CP(a) of the search source. The identification information (SSDP advertise message) includes the ID number (UUID) of the connected device and a device type indicating the type of the connected device. To newly search for devices and services, the CP(a) 801 designates “ssdp:all” in the ST header of the discovery message in UPnP. Then, all devices shown in FIG. 8 reply to the search. Thereby, a service list 817 on the IP network 806 is obtained.
A device incapable of directly accessing and operating devices and services can access them via another device having a capability or knowledge to access the devices and services. For example, in a business phone, a subsidiary unit of a telephone set can access a public network via the master unit. A device in a network can access another device outside the network by using a gateway or a proxy that executes encryption for the device.
Japanese Patent Laid-Open No. 2001-51948 discloses an access control technique of, when a device outside a network requests access to another device in the network, receiving (relaying) the access based on preset access permission conditions or contents.
Japanese Patent Laid-Open No. 2001-346270 discloses a technique related to a home server which has a plurality of pieces of service information to guide the services of a plurality of kinds of home devices and control execution of the services, thereby allowing the user to use the services from a portable device.
The arrangement of the UPnP supporting information processing apparatuses in the network shown in FIG. 8 is expressed as shown in FIG. 2. Referring to FIG. 2, reference numeral 201 denotes a device class in the network. The network includes a camera device 202 having a reproduction service 206 and a photographing service 207, and a data device 203 having a data saving service 208 and a data transmission/reception service 209. The network also includes a printer device 204 having a print service 210, and a scanner device 205 having a data scan service 211.
A CP(a) 212 shown in FIG. 2 can use only the reproduction service 206 of the camera device 202 in the network. That is, when the arrangement of the information processing apparatuses in FIG. 8 is expressed as in FIG. 2, the CP(a) 801 can use only “the reproduction service 808 of the camera device 807” in the service list 817 in the network.
When search is done by designating “ssdp:all” in the ST header of the discovery message in UPnP, all devices shown in FIG. 8, reply to the search so that the service list 817 on the network is obtained. However, even when the CP(a) 801 wants to select and operate the data saving service 813 (data device 812), the operation is impossible because the CP(a) 801 has neither the capability nor the knowledge to operate the device. In addition, the device operation authorization of the CP(a) 801 may be insufficient.
In other words, a control point of UPnP supporting information processing apparatuses may be able to search for usable services in the network but be unable to directly operate them. A control point searches for usable services in the network by designating “ssdp:all” in the ST header of the discovery message or designating a device category or service that can be handled by the control point itself.
Even when the CP(a) 801 has only a capability to transmit data but neither capability nor knowledge to receive data, it is impossible to use only the data transmission service in the data transmission/reception service 814.
Additionally, even when the efficiency can be improved by combining,. for example, the data scan service 811 and print service 816 and using them as a new service (copy service), the CP(a) 801 cannot use the combined service.
In a business phone, a device can access and operate other devices and services which cannot directly be accessed and operated by the device. For example, when the main device connects to one to n master units, one to n subsidiary units connected to each master unit can use the service. However, if the master unit is absent, the subsidiary units can do nothing.
Assume that a PHS is usable as a subsidiary unit, and the main device is a public network. If a master unit exists, a private mode is set between the master unit and the subsidiary unit. If no master unit exists or the master unit is far away, the subsidiary unit can operate in a public mode. In this case, however, the master unit and subsidiary unit are connected in the private mode so that the master unit mediates communication of the subsidiary unit. Even when the master unit exists, it is impossible to provide different services to the respective subsidiary units.
Even in Japanese Patent Laid-Open No. 2001-51948, the access control apparatus that receives access permission only relays communication to a service that is present in the network. Therefore, a device that accesses from outside the network can only use the service in the network by using the access control apparatus.
In Japanese Patent Laid-Open No. 2001-346270, a portable device can be used like a remote controller of a home server. However, services guided on the home server are the services of home devices, which do not change from those usable without the home server (when the portable device is in home).
As described above, it is impossible in the prior arts to use only the subset of a device or service that cannot directly be accessed and operated by a device or to use a combined service of a plurality of services.